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• db optimization - have a total field or query table?

  - by Dorian Fife

  I have an app where users get points for actions they perform - either 1 point for an easy action or 2 for a difficult one. I wish to display to the user the total number of points he got in my app and the points obtained this week (since Monday at midnight). I have a table that records all actions, along with their time and number of points. I have two alternatives and I'm not sure which is better: Every time the user sees the report perform a query and sum the points the user got Add two fields to each user that records the number of points obtained so far (total and weekly). The weekly points value will be set to 0 every Monday at midnight. The first option is easier, but I'm afraid that as I'll get many users and actions queries will take a long time. The second option bares the risk of inconsistency between the table of actions and the summary values. I'm very interested in what you think is the best alternative here. Thanks, Dorian

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• Counting Values in R Vector

  - by GTyler

  I have a large vector of percentages (0-100) and I am trying to count how many of them are in specific 20% buckets (<20, 20-40, 40-60,60-80,80-100). The vector has length 129605 and there are no NA values. Here's my code: x<-c(0,0,0,0,0) for(i in 1: length(mail_return)) { if (mail_return[i]<=20) { x[1] = x[1] + 1 } if (mail_return[i]>20 && mail_return[i]<=40) { x[2] = x[2] + 1 } if (mail_return[i]>40 && mail_return[i]<=60) { x[3] = x[3] + 1 } if (mail_return[i]>60 && mail_return[i]<=80) { x[4] = x[4] + 1 } else { x[5] = x[5] + 1 } } But sum(x) is giving me length 133171. Shouldn't it be the length of the vector, 129605? What's wrong?

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• add two float values in java

  - by user1845286

  acually i try to add two float values in java like this import java.text.DecimalFormat; class ExactDecimalValue { final strictfp static public void main(String... arg) { float f1=123.00000f; float f2=124.00000f; float f3=f1+f2; System.out.println(f1+f2); System.out.println("sum of two floats:"+f3); /*my expected output is:247.00000 but comming output is:247.0 and 247*/ } } Now what i can do to get the value in this format:247.00000. please any one help me. Thanks & Regards venkatesh

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• OOP PHP simple question

  - by Tristan

  Hello, I'm new to OOP in PHP, is that to seems correct ? class whatever { Function Maths() { $this->sql->query($requete); $i = 0; while($val = mysql_fetch_array($this)) { $tab[i][average] = $val['average']; $tab[i][randomData] = $val['sum']; $i=$i+1; } return $tab; } I want to access the data contained in the array $foo = new whatever(); $foo->Maths(); for ($i, $i <= endOfTheArray; i++) { echo Maths->tab[i][average]; echo Maths->tab[i][randomData]; } Thank you ;)

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• suggest an algorithm for the following puzzle!!

  - by garima

  There are n petrol bunks arranged in circle. Each bunk is separated from the rest by a certain distance. You choose some mode of travel which needs 1litre of petrol to cover 1km distance. You can't infinitely draw any amount of petrol from each bunk as each bunk has some limited petrol only. But you know that the sum of litres of petrol in all the bunks is equal to the distance to be covered. ie let P1, P2, ... Pn be n bunks arranged circularly. d1 is distance between p1 and p2, d2 is distance between p2 and p3. dn is distance between pn and p1.Now find out the bunk from where the travel can be started such that your mode of travel never runs out of fuel.

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• Efficiently Reshaping/Reordering Numpy Array to Properly Ordered Tiles (Image)

  - by Phelix

  I would like to be able to somehow reorder a numpy array for efficient processing of tiles. what I got: >>> A = np.array([[1,2],[3,4]]).repeat(2,0).repeat(2,1) >>> A # image like array array([[[1, 1, 2, 2], [1, 1, 2, 2]], [[3, 3, 4, 4], [3, 3, 4, 4]]]) >>> A.reshape(2,2,4) array([[[1, 1, 2, 2], [1, 1, 2, 2]], [[3, 3, 4, 4], [3, 3, 4, 4]]]) what I want: X >>> X array([[[1, 1, 1, 1], [2, 2, 2, 2]], [[3, 3, 3, 3], [4, 4, 4, 4]]]) to be able to do something like: >>> X[X.sum(2)>12] -= 1 >>> X array([[[1, 1, 1, 1], [2, 2, 2, 2]], [[3, 3, 3, 3], [3, 3, 3, 3]]]) Is this possible without a slow python loop? Bonus: Conversion back from X to A Edit: How can I get X from A?

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• jquery filtering content before specific string

  - by jeff

  Is is possible remove all content before a specific string with jquery? For instance say I wanted to strip all the text before the word "subcommittee" in this example below. How would I do that? With losses mounting among hoteliers, fishermen and others whose livelihoods have been curtailed by the spill, frustration is "rapidly escalating" along the Gulf Coast alive." Linn told a House Energy and Commerce subcommittee Monday that the amount of money BP has paid local residents for their losses has typically been about $5,000, a sum he dismissed as "a marketing ploy." Businesses such as his vacation rental company are borrowing money to pay their overhead costs, which he called "the only way we're going to keep our business alive."

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• Create numbers within an array that add up to a set amount

  - by RussellDias

  I'm fairly new to PHP - programming in general. So basically what I need to accomplish is, create an array of x amount of numbers (created randomly) who's value add up to n: Lets say, I have to create 4 numbers that add up to 30. I just need the first random dataset. The 4 and 30 here are variables which will be set by the user. Essentially something like x = amount of numbers; n = sum of all x's combined; create x random numbers which all add up to n; $row = array(5, 7, 10, 8) // these add up to 30 Also, no duplicates are allowed. I need the values with an array. I have been messing around with it sometime, however, my knowledge is fairly limited. Any help will be greatly appreciated. Cheers

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• it is possible to "group by" without losing the original rows?

  - by toPeerOrNotToPeer

  i have a query like this: ID | name | commentsCount 1 | mysql for dummies | 33 2 | mysql beginners guide | 22 SELECT ..., commentsCount // will return 33 for first row, 22 for second one FROM mycontents WHERE name LIKE "%mysql%" also i want to know the total of comments, of all rows: SELECT ..., SUM(commentsCount) AS commentsCountAggregate // should return 55 FROM mycontents WHERE name LIKE "%mysql%" but this one obviously returns a single row with the total. now i want to merge these two queries in one single only, because my actual query is very heavy to execute (it uses boolean full text search, substring offset search, and sadly lot more), then i don't want to execute it twice is there a way to get the total of comments without making the SELECT twice? !! custom functions are welcome !! also variable usage is welcome, i never used them...

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• Assigning Value to a variable that is too big for it! (checked and unchecked concept)

  - by ThickBook

  So when we assign a value to a variable then that variable should be able to hold it, right? and if not compiler produces the error. Now there is an option in C# known as Checked (which is by default) and unchecked option. But is there practical use of unchecked? any comments for a layman? :) Example: int a=int.MaxValue; int b=int.MaxValue; unchecked { int sum=a+b; }

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• question abouut string sort

  - by davit-datuashvili

  i have question from programming pearls problem is following show how to use lomuto's partitioning scheme to sort varying length bit strings in time proportional to the sum oof their length and algorithm is following each record in x[0..n-1] has an integer length and pointer to the array bit[0..length-1] code void bsort(l,u,depth){ if (l>=u) return; for (int i=l;i<u;i++) if (x[i].length<depth) swap(i,l++); m=l; if (x[i].bit[depth] ==0) swap(i,m++); bsort(l,m-1,depth+1); bsort(m,u,depth+1); please help me i need following things 1. how this algorith works 2.how implement in java?

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• CouchDB emit with lookup key that is array, such that order of array elements are ignored.

  - by MatternPatching

  When indexing a couchdb view, you can emit an array as the key such as: emit(["one", "two", "three"], doc); I appreciate the fact that when searching the view, the order is important, but sometimes I would like the view to ignore it. I have thought of a couple of options. 1. By convention, just emit the contents in alphabetical order, and ensure that looking up uses the same convention. 2. Somehow hash in a manner that disregards the order, and emit/search based on that hash. (This is fairly easy, if you simply hash each one individually, "sum" the hashes, then mod.) Note: I'm sure this may be covered somewhere in the authoritative guide, but I was unsuccessful in finding it.

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• what's the name of this language that description another language syntax?

  - by Boolean

  for example: <SELECT statement> ::= [WITH <common_table_expression> [,...n]] <query_expression> [ ORDER BY { order_by_expression | column_position [ ASC | DESC ] } [ ,...n ] ] [ COMPUTE { { AVG | COUNT | MAX | MIN | SUM } ( expression ) } [ ,...n ] [ BY expression [ ,...n ] ] ] [ <FOR Clause>] [ OPTION ( <query_hint> [ ,...n ] ) ] <query_expression> ::= { <query_specification> | ( <query_expression> ) } [ { UNION [ ALL ] | EXCEPT | INTERSECT } <query_specification> | ( <query_expression> ) [...n ] ] <query_specification> ::= SELECT [ ALL | DISTINCT ] [TOP expression [PERCENT] [ WITH TIES ] ] < select_list > [ INTO new_table ] [ FROM { <table_source> } [ ,...n ] ] [ WHERE <search_condition> ] [ <GROUP BY> ] [ HAVING < search_condition > ] whats the language called?

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• How can you get the average of the count of records in Reporting Services

  - by Tim Coker

  I have a report where I'm counting the number of records for a day. At the bottom, I have the total records for that time period. I'd like to display the average records for each day. An example: Day Tests 1/1/2010 5 1/2/2010 10 1/3/2010 8 Average 7.7 Total 23 I can accomplish this by aggregating the data by date in SQL then just doing the Average and Sum of the count from SQL, but that would complicate the report considerably as I'm doing other column filters for the types of tests performed. There seems to be a simple way to accomplish this that I'm missing. I can't do Average(Count(field)) in SSRS, unfortunately. Is there something I'm missing, or is there really not a way to accomplish this simply?

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• SQL Outer joins

  - by dsquaredtech

  Three tables courses,registration,students columns in students firstname,lastname,studentid,major,admitdate,graddate,gender,dob columns in registration courseid,studentid columns in courses coursenumber,coursename,credits select statement I need to modify select lastname as 'Last Name',sum(credits) as 'Credits Registered For' from students as s inner join registration as r on s.studentid = r.studentid inner join courses as c on c.coursenumber = c.courseid group by last name; the question on the lab is... Modify the previous query to show all students, even if they have not registered for a class. You should have 14 rows. Students who are not registered will show NULL in output. I know this requires outer join of some sort but I'm not fully grasping these joins i've read multiple posts on here and other sites but can't seem figure it out.

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• Abort early in a fold

  - by Heptic

  What's the best way to terminate a fold early? As a simplified example, imagine I want to sum up the numbers in an Iterable, but if I encounter something I'm not expecting (say an odd number) I might want to terminate. This is a first approximation def sumEvenNumbers(nums: Iterable[Int]): Option[Int] = { nums.foldLeft (Some(0): Option[Int]) { case (None, _) => None case (Some(s), n) if n % 2 == 0 => Some(s + n) case (Some(_), _) => None } } However, this solution is pretty ugly (as in, if I did a .foreach and a return -- it'd be much cleaner and clearer) and worst of all, it traverses the entire iterable even if it encounters a non-even number. So what would be the best way to write a fold like this, that terminates early? Should I just go and write this recursively, or is there a more accepted way?

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• Using template specialization in C++

  - by user550413

  How can I write a function using template specialization that has 2 different input types and an output type: template <class input1, class input2, class output> and return the sum of the 2 numbers (integers/doubles). However, if I get 2 integers I want to return an integer type but for any other combinations of integer and double I'll always return double. I am trying to do that without using directly the '+' operator but having the next functions instead: double add_double_double(double a, double b) {return (a+b);} double add_int_double(int a, double b) {return ((double)(a)+b);} int add_int_int(int a, int b) {return (a+b);}

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• User's possibilities on site

  - by Lari13

  I want to build a system on the website, that allows users to do some things depend on their rating. For example I have rule for rating value X: 1 post in 3 days 10 comments in 1 day 20 votes in 2 days for rating value Y, rule may be following: 3 post in 1 day 50 comments in 1 day 30 votes in 1 day Each night I recalculate users' ratings, so I know what each user is able to do. Possibilities don't sum or reset on each rating's recalculation. One more important thing is that admin can fill concrete user's possibilities at any time. What is optimal database (MySQL) structure for desired? I can count what concrete user has done: SELECT COUNT(*) FROM posts WHERE UserID=XXX AND DateOfPost >= 'YYY' SELECT COUNT(*) FROM comments WHERE UserID=XXX AND CommentOfPost >= 'YYY' But how can I do admin filling possibilities in this case?

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• How to add up amount of data from an external file in C# (Stream Reader)

  - by user2985995

  I'm new to this site, and pretty new to programming, at the moment I'm trying to display a count amount for the users names on my donation list, and then I also want to have a sum to work out the total amount of money the donation list contains, If someone could help me with creating a way to add up amount of donors on the donations.txt file that would be great help, I have no idea where to start, but so far this is my coding: string sName; double dAmount; string sTotalNames; double dAmountTotal; double dAmountAverage; using (StreamReader sr = new StreamReader("Donations.txt")) { while (sr.Peek() != -1) { sName = sr.ReadLine(); Console.WriteLine(sName); dAmount = Convert.ToDouble(sr.ReadLine()); Console.WriteLine(dAmount); } Console.WriteLine("Press any key to close"); Console.ReadKey(); }

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• recursive enumeration of integer subsets?

  - by KDaker

  I have an NSArray of NSNumbers with integer values such as [1,10,3]. I want to get the sum of all the possible subsets of these numbers. For example for 1,10 and 3 i would get: 1, 10, 3, 1+10=11, 1+3=4, 10+3=13, 1+10+3=14 there are 2^n possible combinations. I understand the math of it but im having difficulties putting this into code. so how can i put this into a method that would take the initial array of numbers and return an array with all the sums of the subsets? e.g -(NSArray *) getSums:(NSArray *)numbers; I understand that the results grow exponentially but im going to be using it for small sets of numbers.

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• Writing array to text file

  - by user3661876

  I have an array, but it won't write each index to the text file. Instead it is only writing the last index and the other indexes are not appearing. Can anyone help me to get the entire array printed to the text file? static void solve(int k) { if (k == N) // We placed N-1 queens (0 included), problem solved! { // Solution found! using (StreamWriter sw = new StreamWriter("names.txt")) { Console.Write("Solution: "); for (int i = 0; i < N; i++) { Console.Write(position[i] + " "); foreach (int s in position[i].ToString()) { string list = position[i].ToString(); sw.Write(list + " "); } } Console.WriteLine(); sum += 1; } }

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• How can I improve the performance of this algorithm

  - by Justin

  // Checks whether the array contains two elements whose sum is s. // Input: A list of numbers and an integer s // Output: return True if the answer is yes, else return False public static boolean calvalue (int[] numbers, int s){ for (int i=0; i< numbers.length; i++){ for (int j=i+1; j<numbers.length;j++){ if (numbers[i] < s){ if (numbers[i]+numbers[j] == s){ return true; } } } } return false; }

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• PHP query for totals of products for last six months

  - by user2260925

  I need to get the figures for the last six months from my orders table. The table has the following fields: qty, product, price, code, The format of the report must be as follows: Month: Jan Feb Mar Apr May June Product1 7 5 4 6 8 9 Product2 8 3 1 4 7 7 Product3 5 4 1 7 7 6 My current code gets the figures for one month only: "SELECT product,building, SUM(qty) AS 'month1' FROM sh_orders WHERE MONTH(order_date) = MONTH(CURDATE()) GROUP BY product"; The code to show it is: echo " <td> ". $row['product']. "</td> <td> ". $row['month1']. "</td>; Any help is greatly appreciated.

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• C Different answers for a variable when running 'Debug' and 'Start without debug'

  - by Craz

  I keep getting this weird output from my code everytime I use the 'start without degugging' (ctrl-F5) as opposed to normal 'debug' (F5). When I try to find the following value of norm_differnece in debug (pressing F5) mode, it gives me the correct answer for norm_difference normdifference = 1.000000 but in 'start without debugging' (pressing ctrl-f5) the wrong output normdifference = 1456816083547664100000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000.000000 The following is a segment of code which is gives the output Note: X[] = is a array of stored DOUBLE values for(i=0;i<n;i++){ sum_difference += (pow((X[i*n]-X[i]),2)); } norm_difference = sqrt(norm_difference); for(i=0;i<n;i++){ sum_norm_1 += pow(X[i],2); } norm_1 = sqrt(norm_1); //Take square root of the sum of squares for the row printf("normdifference = %f \n norm_1 = %f \n",norm_difference,norm_1);

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• What is this kind of chaining in C# called?

  - by Thinking

  Can you please tell me what kind of construct in C# is this. Code Golf: Numeric equivalent of an Excel column name C.WriteLine(C.ReadLine() .Reverse() .Select((c, i) => (c - 64) * System.Math.Pow(26, i)) .Sum()); Though I am new to C# (only two months exp so far), but since the time I have joined a C# team, I have never seen this kind of chaining. It really attracted me and I want to learn more about it. Please give some insight about this.

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